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%I #7 Oct 12 2018 09:32:11
%S 44,226,1150,5874,29970,152974,780718,3984650,20336682,103793974,
%T 529740902,2703678866,13798968738,70426836510,359442745310,
%U 1834515000218,9362952299866,47786404483974,243891069807254,1244765212590370
%N Number of (n+1) X (1+1) 0..2 arrays with every 2 X 2 subblock having the sum of the absolute values of the edge differences equal to 4.
%H R. H. Hardin, <a href="/A233942/b233942.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 5*a(n-1) + 3*a(n-2) - 13*a(n-3) + 2*a(n-4).
%F Empirical g.f.: 2*x*(22 + 3*x - 56*x^2 + 9*x^3) / (1 - 5*x - 3*x^2 + 13*x^3 - 2*x^4). - _Colin Barker_, Oct 12 2018
%e Some solutions for n=5:
%e ..0..1....1..2....2..1....2..0....1..2....2..0....2..0....1..2....0..0....2..2
%e ..0..2....0..2....1..0....1..0....1..0....1..0....0..0....1..0....2..2....0..2
%e ..0..2....2..2....2..1....2..0....1..2....1..2....2..2....2..0....2..0....0..0
%e ..2..2....0..1....0..0....2..2....2..1....1..0....2..0....2..2....1..1....2..0
%e ..0..2....0..2....2..1....2..0....0..1....0..1....1..0....2..0....0..2....2..0
%e ..0..2....2..2....0..1....1..1....2..1....0..2....0..1....0..0....2..2....2..2
%Y Column 1 of A233949.
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 18 2013
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